教案
《Welding professional English》Teaching Plan
新课讲授Teaching new lesson 课文 Text 钨极惰性气体保护
In gas tungsten arc welding (GTAW), a virtually non-consumable tungsten electrode is used to provide the arc for welding. During the welding cycle a shield of inert gas expels the air from the welding area and prevents oxidation of the electrode, weld puddle, and surrounding heat-affected zone. See Figure 2-11.
在钨极惰性气体保护焊中，一根不熔化的钨极被用来为焊接提供电弧。

在焊接期间，利用惰性气体保护，排除了焊接区的空气并防止电极、熔池和周围热影响区的氧化，如图2-11所示。

In GTAW, the electrode is used only to create the arc. It is not consumed in the weld.
在GTAW焊中，电极只是用来产生电弧，它不会熔化并填充到焊缝中。

In this way it differs from the regular shielded metal arc welding process, where the stick electrode is consumed in the weld.
这样，钨极惰性气体保护焊不同于普通的焊条电弧焊。

在焊条电弧焊中，焊条熔化并进入焊缝。

句中“it”是指“gas tungsten arc welding”；“where”引导的是定语从句，修饰前面的“shielded metal arc welding process”，“where”是连接副词，相当于“in which”。

For joints where additional weld metal is needed, a filler rod is fed into the puddle in a manner similar to the oxy-acetylene welding.
对于需要添加填充金属的焊接接头来说，可以把一根焊丝送入熔池，其填充方法与氧乙炔焊相似。

句中“For”表示“对……来说”；“where”是连接副词，引导定语从句，修饰前面的“joints”，“where”相当于“in which”；。